GABA- and glutamate-mediated network activity in the hippocampus of neonatal and juvenile rats revealed by fast calcium imaging.

摘要: Abstract In the rat hippocampus, during first postnatal week, network activity is characterized by GABA-driven giant depolarizing potentials (GDPs) associated with calcium signals that are readily blocked when GABA A antagonist bicuculline applied to bath. Towards end of in concomitance shift responses from hyperpolarizing direction, functional glutamatergic connections start appearing. At this developmental stage, application blocks -mediated inhibition and induces appearance interictal epileptiform discharges. present experiments, we have used a high spatio-temporal resolution imaging system compare, on time scale tens ms, onset propagation fast transients generated within GABAergic or network. We found that, evoked GDPs arise activation local circuitry neurons spanning stratum radiatum pyramidal layer. Similar patterns were elicited focal presence kynurenic acid, broad spectrum ionotropic antagonist, bicuculline. During second bicuculline, discharges stimulation fibres propagated along well-defined three-synaptic pathway dentate gyrus CA1 hippocampal area.